The master socket contain a surge arrestor and an R/C circuit filter these are used by your service provider to get a fixed value resistance when they run line checks.
Standard BT type socket with screw type terminals
Flat Plate low profile design
Ultra low profile design with built in gasket
Certified to BS 5733
Minimum mounting box depth: 25mm
Dimensions: 87.5mm x 87.5mm
IP Rating: IP20
15 Year Warranty